Noted environmentalist GD Agarwal, who was on 'fast-unto-death' since June 22 over Ganga cleaning, died on Thursday. The 87-year old IIT professor-turned-saint had been on a fast against the authorities in Haridwar's Kankhal area. Agarwal, who was taking only water mixed with honey for the last 110 days, had shunned intake of his only diet on Wednesday.